.pure-block {
    position: relative;
}

.pure-block::before {
    content: "";
    padding-top: calc(100% / (var(--pure-block-aspect-ratio, var(--pure-block-aspect-ratio-prop))));
    display: block;
}

.pure-block-content {
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: 0;
    width: 100%;
    height: 100%;
}
